1. Field of the Invention
The present invention relates a display such as a liquid crystal display, and specifically to a capacitive type touch sensor allowing information to be inputted thereinto by bringing a finger or the like of a user into contact with or close to the touch sensor, and a display and an electronic unit including such a touch sensor.
2. Description of the Related Art
In recent years, attention has been given to a display in which a contact detection device (hereinafter referred to as “touch sensor”) so-called touch panel is directly mounted on a liquid crystal display and various buttons are displayed on the liquid crystal display so that information is allowed to be inputted by the buttons instead of normal buttons. This technique provides large advantages of space saving and a reduction in the number of components in a trend toward larger screen sizes of mobile devices, because a display and buttons are allowed to be located in a common area. However, in this technique, there is an issue that mounting of the touch sensor causes an increase in the whole thickness of a liquid crystal module. In particular, in the case where the touch sensor is applied to a mobile device, a protective layer for preventing scratches on the touch sensor is necessary, so liquid crystal modules have a tendency to have a larger thickness, and the tendency goes against a trend toward thinner liquid crystal modules.
Therefore, for example, as described in Japanese Unexamined Patent Application Publication No. 2008-9750 and U.S. Pat. No. 6,057,903, liquid crystal display elements with a touch sensor in which a capacitive type touch sensor is formed have been proposed so as to reduce the thickness of the liquid crystal display element. In this case, a conductive film for the touch sensor is arranged between an observation-side substrate of the liquid crystal display element and an observation-side polarizing plate arranged on an outer surface of the observation-side substrate, and the capacitive type touch sensor which has an outer surface of the polarizing plate as a touch surface is formed between the conductive film for the touch sensor and the outer surface of the polarizing plate. Moreover, a display with a built-in touch sensor has been proposed, for example, as described in Published Japanese Translation No. S56-500230 of PCT International Application.